Revolving paper knife



Oct. 1, 1935. v THOMPSQN 2,015,877

REVOLVING PAPER KNIFE Filed Dec. 5, 1954 INVENIOR. W670i? ((777/001PSO/V Fi -m 1 3 K BYJFM ATTORNEY.

Patented Oct. 1, 1935 REVOLVING PAPER KNIFE Victor T. Thompson,Montevista, 0010., assignor to Harold E. Thempson, Camas, Wash.

Application December 3, 1934, Serial No. 755,786

6 Claims. (01. 164-40) UNITED STATES A'E'ENT OFFICE My invention relatesto a device for cutting a roll of paper into shorter lengths after it istightly rolled and leaving a smooth surface at the point of severance.

It is particularly applicable to trimming rolls of paper, the ends ofwhich have become damaged in shipment, but its greatest use probablywill be in the manufacture of short rolls of paper such as sanitarypaper, adding machine rolls and the like.

It has heretofore been necessary to cut the paper into the requiredwidth before rolling since, owing to the high co-efficient of frictionof paper generally, a sharp edged knife cannot be used without burningboth the knife and the paper, and a saw obviously leaves a very roughedge, which is undesirable.

The invention consists essentially of a pair of sharp edged cuttingdiscs held on a shaft in spaced relationship, the spacing member being asaw slightly smaller than the discs. The function of the saw is toremove the shreds of paper after they are severed, to prevent frictionon the adjacent sides of the cutter" discs, which are slightly concavedon their outer surfaces to prevent friction on the other sides.

The following drawing illustrates a preferred way of embodying theinvention in a useful tool, in which,-

Fig. I is a side elevation of my new revolving paper knife in operativeposition, partly broken away to show its construction and shown engagedwith a roll of paper which is being separated into two parts; I

Fig. II is an orthographic projection of Fig. I;

Fig. III is a detail of the cutting edge of my new revolving paper knifewith some of the parts somewhat exaggerated for the purpose of a clearershowing of their construction as hereinafter pointed out;

Fig. IV is the same structure shown in Fig. III but more nearly as itwill appear as actually constructed.

The revolving paper knife consists essentially of two sharp edged discsI and 2, provided with beveled edges la and 2a, the discs being slightlyconcave on the outside as shownat lb and 212. For the purpose of clearerillustration of this in the drawing the concavity is shown muchexaggerated. Actually it will be on the order of thousandths of an inchinstead of on the order of 32nds of an inch as might be suggested by thedrawing of Fig. III. The purpose of this concavity, or it might becalled relief, is to prevent the surface of the cutter back of the edgeproper from contacting the roll of paper at the point of severance andduring severance.

Mounted between the discs is a saw 4, having a diameter slightly lessthan the diameter of the discs I and 2. This saw will have fine teethand 5 preferably there is a little set in the teeth and the thickness ofthe elements is as little as possible with the required stability.

The three elements consisting of the disc I, the disc 2 and the saw 5are assembled between 001- lars 5 and 6 after the known manner andrigidly mounted upon a shaft 1 which will be provided with suitablebearings and connected to power means for revolving the saw at a highspeed. I have found that a peripheral speed of the order of 6000 feetper minute is suitable, and it should be brought to full speed beforebeing applied to the paper roll indicated by numeral It). The sharpedged discs l and 2, should be made of a high grade of steel suitablefor the purpose and tempered according to the known art for such use.

In operation the revolving paper knife will remain relatively fixed andthe paper rolls to be divided into short lengths will be moved to thepaper knife or knives by suitable conveyor means, which has not beenshown as it is no part of this invention; and/or the revolving paperknife may be mounted upon a hanger, allowing it to swing to the workmuch as a swinging cut-off saw is used in the lumber industry.

When my new revolving paper knife is brought to its proper speed and itsedge brought in contact with a paper roll, the action is this. The edgesof the revolving sharp edged cutters penetrate several sheets of paperahead of the saw which removes a narrow kerf between the two sharp edgedcutters. This action is extremely rapid, accomplished without anyburning effect on the edges of the severed rolls which are notdiscolored and which have severance surfaces so smooth as to appearsolid. Very little waste of paper stock is occasioned by the kerf ormaterial removed from the roll, hence the operation is not onlyextremely rapid but is also economical.

I do not wish to restrict myself to any style of mounting or any purposefor which this revolving paper cutting knife may be used, but only tothe extent indicated by the subjoined claims.

1. A paper roll cutter comprising a pair of sharp edged discs, 2. sawthat is of less diameter than the discs and a mounting to hold the discsrigidly, one on each side of the saw.

2. The structure according to claim 1, charac terized by each disc beingconcave on the side opposite the saw.

3. In a revolving paper knife, a pair of beveledged cutting discsassembled in opposed relationship and mounted for revolution with theirbeveled edges inward and a saw member of less diameter than the discsthat is rigidly held be-- tween said discs.

4. The combination according to claim 3 characterized by the teeth ofthe saw being provided with set and extending laterally into the spaceprovidedby beveling the discs.

5. As a new article of manufacture, a revoluble paper roll cuttercomprising structures presenting two peripheral knife edges spaced apartand saw teeth between the knife edges arranged on a circle that issmaller than the circumference of the knife edges.

6. A revoluble circular paper roll cutter comprising in combination ashaft, a pair of sharp edged discs on the shaft, a circular spacingmember between said discs, teeth on said spacing member arranged withtheir points on a circumference that is concentric with but smaller thanthe circumference of the discs and means for clamping the discs and sawin position for unitary operation with the shaft.

VICTOR T. THOMPSON.

